Automatic fire alarm



Jan. 4, 1955 HUGHES ETAL 2,698,890

AUTOMATIC FIRE ALARM Filed July 9, 1951 Fig.2

3 Bl-METALL/C H93 Edward H. Hughes Henry M- Garrett Wesley 5. Garrett INVENTORS.

BY mm United States Patent AUTOMATIC FIRE ALARM Edward H. Hughes, Henry M. Garrett, and Wesley S. Garrett, Bastrop, La.

Application July 9, 1951, Serial No. 235,881

2 Claims. (Cl. 200-139) The present invention relates to improvements in fire alarms and more particularly to a fire alarm which is adapted for home use.

An object of the present invention is to provide a simple automatic fire alarm which embodies the provision of a thermo-responsive coil which is adapted to complete the circuit for an alarm upon a predetermined rise in temperature.

A further object of the present invention resides in the provision of means whereby the temperature at which the alarm is set off can be preselected without changing the thermo-responsive coil.

Other objects of the present invention are to provide an automatic fire alarm which is exceedingly simple in construction and economical of manufacture.

Various other objects and advantages will become apparent from the detailed description to follow. The best forms in which we have contemplated applying our invention are clearly illustrated in the accompanying drawings, wherein:

Figure 1 is a detailed perspective view of the first form of automatic fire alarm shown in the circuit with the alarm;

Figure 2 is a front elevational view of a modified form of automatic fire alarm; and,

Figure 3 is a vertical transverse sectional view taken substantially along the plane of line 33 of Figure 2.

Referring more particularly to the drawings, wherein like numerals designate like parts throughout, the numeral designates generally the first form of automatic fire alarm adapted for use in combination with an alarm 12 of conventional form.

The automatic fire alarm 10 is comprised of a common support base 14 to which is centrally attached the substantially U-shaped supporting brackets 16, the brackets having angulated ends 18 and 20 for securement to the base 14. The thermo-responsive coil of spring form 26 has its innermost end secured to the pin 28, the pin 28 being rotatably disposed in the legs 22 and 24 of the U-shaped bracket 16. The outer end of the coil 26 is of flat form and is disposed on the base 14, as seen at 30. The end 30 is formed with an elongated slot 32 through which the lug 34 secured to the base 14 can upwardly extend. A nut 36 is engaged on the lug 34 whereby the tension of the coil 26 can be adjusted by adjustment of the end 30 relative to the base 14.

On opposing sides of the U-shaped bracket 16 are disposed a pair of upstanding elements 38 and 40 which have their lower ends angulated at 42 and 44 for securement to the base 14. The angulated portions 42 and 44 are each provided with upstanding lugs to which the wire ends 46 can be secured by means of the nuts 48. The wires 50 and 52 are connected to the conventional alarm 12 and a source of electric power. Each of these elements 38 and 40 have an outstanding contact post 54 and 56 extending therefrom.

The pin 28 has a contact rod 58 secured thereto for rotation therewith and the contact posts 54 and 56 extend into the plane of rotation of said contact rod 58.

It will thus be seen that upon a predetermined rise in temperature, the coil 26 will effect rotation of the pin 28 and rod 58 whereby the outer ends of the rod 58 will contact the posts 54 and 56 for completing the circuit to the alarm 12. A suitable casing 60 could be provided for the alarm but constitutes no part of the present invention.

In the form of the invention shown in Figure 2, the

thermo-responsive coil 26' has its inner end connected to the pin 28' while its outer end is secured to the pin 62 extending through the upper portions of the legs 22 and 24 of the U-shaped bracket 16. The pin 28 has a contact rod 58' connected thereto for rotation therewith upon changes in temperature.

On opposing sides of the U-shaped bracket 16 are disposed a pair of arcuate straps 64 and 66 which are secured to the base 14. The straps 64 and 66 are formed with elongated arcuate slots 68 and 70. Each of the slots 68 and 70 has a contact post 72 and 74 adjustably secured therein by means of a pair of nuts 76.

It will thus be seen that upon a predetermined rise in temperature, the contact 58 will contact the contact posts 72 and 74, completing the circuit for an alarm. The alarm can be set for various temperatures by adjusting the positioning of the posts 72 and 74 in the slots 68 and 70.

Details of the construction are shown best in Figure 3 wherein the pin 28' is shown as having a threaded end 78 to which the internally threaded sleeve 80 can be secured by supporting the rod 58 for rotation with the pin 28.

The inner end of the coil 26 terminates in a sleeve 32 which encircles the pin 28 and is secured thereto. The pin 28' is rotatably journaled in the legs 22 and 24 of the U-shaped bracket 16, a washer 84 being carried by the end of the pin having a retaining pin 86 extending therethrough.

in view of the foregoing, it is believed that an automatic fire alarm has been provided which will accomplish all of the objects hereinabove set forth. Furthermore, in view of the simplicity of the alarm, a more detailed description is deemed unnecessary.

Having described our invention, what is claimed as new is:

1. A fire alarm mechanism comprising a supporting bracket having a thermal responsive coil supported thereby, the outer end of said coil being secured to said bracket and the other centrally disposed end being secured to a pin rotatably journaled in said bracket, said coil being responsive to temperature change to effect rotation of said pin, a pair of diametrically opposed contact posts connected in an alarm circuit, a contact rod secured to said pin for rotation therewith, said contact posts extending into the plane of rotation of said contact rod whereby a predetermined rise in temperature effects contact between said rod and posts to complete the alarm circuit, a pair of upstandnig straps fixedly secured to a base support common to said supporting bracket, said posts being insulated from each other and from said bracket, said straps being formed with arcuate slots, and said contact posts being adjustably disposed in said slots whereby various preselected temperature changes can effect contact between said rod and posts.

2. An automatic fire alarm comprisin' a base member, a U-shaped bracket mounted on said base, a pin rotatably mounted transversely of said bracket, a spiral thermoresponsive element, one end of said element being fixed to said pin, the other end of said element being fixed to said bracket, a contact rod fixed transverse of said pin, a pair of terminal elements mounted on said base, said terminal elements being disposed on opposite sides of said bracket and insulated therefrom, a contact post on each of said terminal elements, said posts extending into the plane of rotation of said contact rod whereby rotation of said contact rod produces bridging of said posts.

References Cited in the file of this patent UNITED STATES PATENTS 1,618,322 Bettenhausen Feb. 22, 1927 1,641,170 Karlson Sept. 6, 1927 1,672,729 Pape -1 June 5, 1928 1,931,238 Phelan Oct. 17, 1933 1,976,954 Mantz Oct. 16, 1934 2,534,103 Camilli Dec. 12, 1950 2,556,582 Hansen June 12, 1951 FOREIGN PATENTS 8,759 Great Britain Apr. 13, 1909 958,043 France Sept. 5, 1949 

